mpenrow mpenrow - 9 days ago 5
C# Question

Convert DataTable to IEnumerable<T>

I am trying to convert a DataTable to an IEnumerable. Where T is a custom type I created. I know I can do it by creating a List but I was think there was a slicker way to do it using IEnumerable. Here is what I have now.

private IEnumerable<TankReading> ConvertToTankReadings(DataTable dataTable)
{
var tankReadings = new List<TankReading>();
foreach (DataRow row in dataTable.Rows)
{
var tankReading = new TankReading
{
TankReadingsID = Convert.ToInt32(row["TRReadingsID"]),
TankID = Convert.ToInt32(row["TankID"]),
ReadingDateTime = Convert.ToDateTime(row["ReadingDateTime"]),
ReadingFeet = Convert.ToInt32(row["ReadingFeet"]),
ReadingInches = Convert.ToInt32(row["ReadingInches"]),
MaterialNumber = row["MaterialNumber"].ToString(),
EnteredBy = row["EnteredBy"].ToString(),
ReadingPounds = Convert.ToDecimal(row["ReadingPounds"]),
MaterialID = Convert.ToInt32(row["MaterialID"]),
Submitted = Convert.ToBoolean(row["Submitted"]),
};
tankReadings.Add(tankReading);
}
return tankReadings.AsEnumerable();
}


The key part being I am creating a List then returning it using AsEnumerable().

Answer

Nothing wrong with that implementation. You might give the yield keyword a shot, see how you like it:

private IEnumerable<TankReading> ConvertToTankReadings(DataTable dataTable)
    {
        foreach (DataRow row in dataTable.Rows)
        {
            yield return new TankReading
                                  {
                                      TankReadingsID = Convert.ToInt32(row["TRReadingsID"]),
                                      TankID = Convert.ToInt32(row["TankID"]),
                                      ReadingDateTime = Convert.ToDateTime(row["ReadingDateTime"]),
                                      ReadingFeet = Convert.ToInt32(row["ReadingFeet"]),
                                      ReadingInches = Convert.ToInt32(row["ReadingInches"]),
                                      MaterialNumber = row["MaterialNumber"].ToString(),
                                      EnteredBy = row["EnteredBy"].ToString(),
                                      ReadingPounds = Convert.ToDecimal(row["ReadingPounds"]),
                                      MaterialID = Convert.ToInt32(row["MaterialID"]),
                                      Submitted = Convert.ToBoolean(row["Submitted"]),
                                  };
        }

    }

Also the AsEnumerable isn't necessary, as List<T> is already an IEnumerable<T>